Motor compressor



' April 21, 1936.

' INVENTOR- Raul Qauzras- Pescara .A-r-vo Nev' Patented Apr. 2l, 1:936

UNITED STATES PATENT oFFlcE Germany June 7, 1932- 1'3 claims. (ci. 23o- 56) My invention relates to motor compressors of the type including a pair of opposed -pistons the inner ends of which reciprocate freely in a common central cylinder and the outer ends of which are adapted to reciprocate in two outer cylinders providedwith suitable valves for compressing air or any other uid into a reservoir. In motor-,compressors of that type a mixture of air and fuel is admitted into the central cylinder between the two pistons and caused to explode at the proper time so as to drive outwardly the two pistons. The inward stroke of said pistons takes place under the action ofthe cushions of air that remain in the dead spaces of the outer cylinders at the end of the outward or compression stroke.

One object of the present invention is to provide a compressor of that type with automatic regulating means for al1owing`air to escape from the outer cylinders during a portion of the outward stroke of the pistons, said means being suddenly brought into play as soon as the pressure in the reservoir reaches a certain value, -so as to reduce or even bring to zero the output of the compressor, and being suddenly brought out of action when the pressure in the reservoir falls below a certain value. y

Another object of my invention is to provide a compresson of that kind in which the correct return lor inward stroke of the pistons is insured under all conditions of work.

A further object of my invention is to provide a compressor provided with the automatic regulating means above referred to in which the injection of fuel into the central cylinder is automatically regulated in accordance with thereonditions of work ofthe machine.

Still further objects of my invention will appear from the following detailed description ,of a preferred embodiment of my invention with referencevtothe accompanying drawing, given merely by way of example, and in which:

Fig. l is a diagrammatic View showing in longitudinal section azmotor compressor according to my invention; and,

Fig. 2 is a diagram illustrating the operation of the compressor. 1

As shown in Fig. 1,'the inner ends of pistons II and I2 are adapted to reciprocate in central cylinder I3, while their outer ends are adapted to reciprocate in a fluid-tight vmanner in outer compressing cylinders I4 and I5 4 respectively. The movements of said pistons are synchronized through connecting rods I6 and cranks I8 adapted to rotate about the axis yof shaft I1. The pisin, say, cylinder I5,

tons insure the distribution by uncovering inlet and outlet ports I9 and 20 controlled by suitably regulated valves I9a and y29a respectively. 'Ihe fuel is injected into cylinder I3 by meansof a pump 8l. K 5

The outer ends of cylinders I4 and I5 are connected with compressed air reservoir 25 throughV valves 23 and conduits 24. Cylinders I4 and I5 are further provided with outlet valves '12 and 13 tted inrecesses 19 and 1I and which are con` l0 trolled through mechanisms that will be hereinafter described.

'I'he variations of the pressure in one oi.y said cylinders '|4, I5 according to the position `of the piston in said cylinder are shown inthe diagram 15 of Fig.. 2. The pressures are plotted-in ordinates and the positions of the cylinderin abscissas. When the compressor is running under full load, valves 12 and 13 being closed, thediagram of pressures is N-O-P-Q and the energy for the 20 return of the pistons is proportional to area I-P-Q. When the compressor is running idle, valves 12 and 13 areopen and the compression instead of starting from N, starts only when piston I2 has covered the whole 25 of recess 1I, that is to say from point Q of the diagram. 'I'he compression curve QP is substantially the same as the expansion curve PQ so that the energy for the return stroke of piston I2, which is proportional to area Q-P-L is sub- 30 stantially the same in the case of the compresor running idle as in the case of the compressor running under full load.

Valves 12, 13 are controlled by rocking members 16, 11, which are actuated by two stops 19 35 and 80 carried by a sliding rod 18. The valves are brought back into their closed positions by return springs 14 and 15.

Rod 18 is actuated through a finger 93 lby a lever 94 provided with a slide for said linger and 40 pivoted about axis 95. Said leveris subjected to the action of a spring 96 the other end 91 of which is iixed to a sliding rod 98 integral with a piston 99 adapted to slide in a cylinder |02. One of the faces of said piston 99 is subjected to the 45 air pressure in reservoir 25 througha tube I 0I While the other face of said piston is subjected tothe action of a spring |00 the strength of which is adjustable.

The output of pump 84 can be adjusted through 50 a rod 85 controlled by a rocking member 86. Said rocking member is actuated by a rod 88 xed to a piston 89 adapted to slide in a cylinder 99one end of which `is connected, through tube 92 with reservoir 25. One face of said piston 89 is there- 55 fore subjected to the pressure of the compressed air in said reservoir while the other face is subjected to the action of a spring Si the strength of which'is adjustable. Furthermore, a stop l1 carried bysliding rod 18 is adapted to actuate rocking member It.

Rockshait I1. which carries the eccentric Il through which pump Il is actuated is provided at its end with a slotted piece IM which, only for certain positions of the slot, allows a stop ill carried by sliding rod 18 to pass freely.

'Ihe operation of the device is as follows:

If there are but small variations of pressure in reservoir 2i, regulation takes place through variation o! the output oi! the injecting pump, which is controlled by the position oi piston I! in cylinder 0l, through rod 88, rocking member I0 and rod Il.

On the contrary, if the pressure -in reservoir 2l becomes so high that a correct return stroke o! pistons II and i2 could no longer be insured, piston l! moves a relatively great distance toward th left hand side and, due to the displace-v ment oi! rod tl, spring 98 takes the position shown in dotted lines in the ligure, thus causing lever I4 to swing toward the left hand side oi the ngure and to drive sliding rod 18 together with it. Stops 1l and lil cause valves 12 and 13 to be opened and the compressor now runs idle. Simultaneously, stop l1, acting on rocking member 8B, causes rod It to be brought into the position that insures the proper 4output ci the pump for the new conditions oi. running.

It might be injurious to a good working of the motor compressor to open valves 12 and 13 at a time corresponding to certain positions of rockshait i1, but owing to the presence of piece IM provided with a slot adapted to allow the passing of stop IM therethrough only when the rockshaft is is not in said positions, any danger from that direction is avoided.

Of course, if no margin of regulation'is required when the compressor is running under full load, due to the stability of the motor compressor, control 88 can be dispensed with.

While I have describedwhat I deem to be a practical and emcient embodiment oi! my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of my invention as comprehended within the scope of the appended claims.

What I claim is:

l. A motor compressor of the type described, comprising in combination, a cylinder, a pair of opposed pistons adapted to reciprocate in said cylinder in opposite directions, means for admitting fuel and `air into said cylinder between said pistons, two cylinders adapted to receive the outer ends of said pistons respectively, a storage reservoir for compressed air, check valves in the outer ends of said two cylinders for connecting them with said reservoir, means for admitting air into said cylinders during the inward stroke of the pistons, means for allowing air to escape from the last mentioned two cylinders during a portion of the outward stroke of the pistons, and means, sensitive to the air pressure in said reservoir, for

controlling the last mentioned means.

2. A motor compressor of the type described,A comprising in combination, a cylinder, a pair of opposed pistons adapted to reciprocate lin said cylinder in opposite directio means for admitting iuel and air into said cylinder between said pistons, two cylinders adapted to receive the outer ends o! said pistons respectively, a reservoir for the compressed air, check valves in the outer ends of the two last mentioned cylinders for cons necting them with said reservoir, means for admitting air into the two last mentioned cylinders din-ing the inward stroke of the pistons, means for allowing air to escape from the two last mentioned cylinders during a portion oi' the outward l0 stroke of the pistons, means for controlling the amount of fuel admitted into the first mentioned cylinder. and means, sensitive to the air pressure in the reservoir, for controlling simultaneously the two last mentioned means. r6

3. A motor compressor oi the type described, comprising in combination, a cylinder, a pair of opposed pistons adapted to reciprocate in said cylinder in opposite directions, means for admitting fuel and air into said cylinder between said 20 two pistons, two cylinders adapted to receive the outer ends of said pistons respectively, a reservoir for the compressed air, check valves in the outerv ends of the two last mentioned cylinders i'or connecting them with said reservoir, means for ad- 25 mitting air into the two last mentioned cylinders during the inward stroke oi the pistons, at least ,one valve provided in the wall of each of the two last mentioned cylinders at an intermediate point oi' its length, elastic means for urging said valves 30 in their closed positions, means, sensitive to the air pressure in said reservoir, for opening said valves when said air pressure rises above a given value and allowing them to be closed by said elastic means when said air pressure falls below 3 a given value, and means, operatively connected with the last mentioned means, for reducing the amount of fuel admitted into the ilrst mentioned cylinder when the valves are opened and increas-l ing it when they are closed.`

4. A motor compressor o! the type described, comprising in combination, a cylinder, a pair of opposed pistons adapted to reciprocate in said cylinder in opposite directions, means for admit'- ung air inte said cylinder between said two pis- 45 tons, a pump. for injecting fuel into said cylinder between said pistons, two compression cylinders adapted to receive the outer ends of said pistons respectively, a reservoir for the compressed'air, check valves in the outer ends of the two last mentioned cylinders for connecting them with said reservoir, means for admitting air into the two last mentioned cylinders during the inward stroke of the pistons, at least one valve provided in. the wall of each of the two last mentioned cylinders at an intermediate point of its length, elastic means for urging said valves toward their closed positions, a cylinder, a piston in the last mentioned cylinder, a tube connecting one end of the last mentioned cylinder with said reservoir so as to push the last mentioned piston in one direction, a spring urging the last mentioned piston into the opposite direction, a tripping mechanism operatively connected with the last mentionedy piston, means operated by said tripping mechanismk for opening the last mentioned valves when the tripping mechanism is in one position and for allowing said last mentioned valves to be closed by said elastic means when the tripping mechanism is in the other position, and means actuated by said tripping mechanism for varying the feed oi said pump.

5. A compressor according to claim 3 further comprising means.. sensitive to the air pressure said reservoir, for varying the feed of said pump.

7. A compressor according to claim 4 further comprising a, cylinder, a. piston mounted in a iluidtight manner in the last mentioned cylinder, a tube connecting one end of the last mentioned cylinder with saidreservoir, so as to push the last mentioned piston in one direction, a spring urging the last mentioned piston into the opposite` direction, and means operatively connected with the last mentioned piston for varying the feed of said pump.

8. A motor compressor of the type described, comprising in combination, a cylinder, a pair of oppod pistons adapted to reciprocate in said cylinder in opposite directions, means for admitting air into said cylinder between said two pistons, a pump for injecting fuel into said cylinder between said pistons, two compression cylinders adapted to receive the outer ends of said pistons respectively, a reservoir for the compressed air, check valves in theouter ends of the two last mentioned cylinders for connecting them with said reservoir, means for admitting air into the two last mentioned cylinders during the inward stroke of.` the pistons, at least one valve provided in the wall of each of the two last mentioned cylinders at an intermediate point of its length, elastic means for urging said valves toward their closed positions, a rocking member adapted to cooperate with each of the last mentioned valves for opening them, a sliding rod, stops carried by said rod and `adapted to act on said rocking members respectively, a fourth cylinder,v a piston in the last mentioned cylinder, a tube connecting one end of the last mentioned cylinder with said reservoir so as to push the last mentioned 'piston' in one direction, a spring'urging the last mentioned piston into the opposite direction, a tripping mechanism operatively connected with the f last. mentioned piston, means for operatively connecting said tripping mechanism with said sliding rod so that for one position of the tripping mechanism the rocking members are caused by the stops on the rod to open the last mentioned valves, while for the other position of the tripping mechanism they allow the valves to be closed' by said elastic means, a rod for controlling rthe feed of said pump, a rocking member adapted to cooperate with the last mentioned pump, and a stop carried by the sliding rod for actuating the last mentioned rocking member.

9. A compressor according to claim- 8 further comprising means, sensitive to the air pressure in said reservoir for varying the feed of the pump.

10. AV compressor according to claim 8 further comprising a cylinder, a piston iltted in a iluidtight manner in the last mentioned cylinder, a tube connecting one end of the last mentioned cylinder with said reservoir so as to push the last mentioned piston in one direction, and means operatively connected with the last mentioned piston for acting on the last mentioned rocking member. f

11. A motor compressor of the type described, comprising in combination, a cylinder, a. piston adapted to reciprocate. in said cylinder, means for admitting fuel and air into said cylinder, a second cylinder adapted to receive the outer end of said piston, a storage reservoir for compressed air, a check valve in the outer end of said second cylinder for connectingjt with said reservoir, means for admitting air into said second cylinder during the inward stroke of the piston, means for allowing air to escape from the second cylinder during a portion of the outward stroke o f the piston, and means adapted to control the last mentioned means in dependence on the` output of the motor compressor.

12. A motor compressor of the type described, comprising in combination, a cylinder, a piston adapted to reciprocate in said cylinder, means for` said piston, a storage reservoir for compressed"y air, a check valve in the outer endof said second cylinder for connecting it with said reservoir, means for admitting air into said Asecond cylinderdring the inward stroke of the piston, means for allowing air to escape from the second cylinder during a portion of the outward stroke of the piston, means adapted to control the last mentioned means independence on the output of the motor compressor, and means Afor controlling the amount of fuel admitted into the first mentioned cylinder.

13. A motor compressor of the type described, comprising in combination a cylinder, a piston adapted to reciprocate in said cylinder, means for admitting fuel and air into said-cylinder, a second cylinder adapted 'to receive the outer end of said piston, a storage reservoir for compressed air, a check valve in the outer end of said second cylinder for connecting it with said reservoir, means for admitting air into said second cylinder during the inward stroke of the piston, means for allowing air to escape from the second cylinder during a portion ofthe outward stroke of the piston, and means sensitive to the air pressure in said reservoir, for' controlling the last mentioned means.

. RAUL PATERAS PESCARA. 

